Reduce the memory usage for large inputted arrays:

move_alloc.

Author: zoziha

src/stdlib_math_diff.fypp

@@ -47,7 +47,8 @@ contains
             work(1:size(work)-i) = work(2:size(work)-i+1) - work(1:size(work)-i)
         end do
 
-        y = work(1:size(work)-n_)
+        call move_alloc(work, y)
+        y = y(1:size(y)-n_)
 
     end function diff_1_${k1}$
 
@@ -92,11 +93,12 @@ contains
             if (size_prepend > 0) work(1:size_prepend, :) = prepend
             work(size_prepend+1:size_x+size_prepend, :) = x
             if (size_append > 0) work(size_x+size_prepend+1:, :) = append
-            do i = 1, n_
+            do concurrent (i = 1:n_)
                 work(1:size(work,1)-i, :) = work(2:size(work)-i+1, :) - work(1:size(x, 1)-i, :)
             end do
 
-            y = work(1:size(work)-n_, :)
+            call move_alloc(work, y)
+            y = y(1:size(y)-n_, :)
 
         elseif (dim_ == 2) then
             allocate(work(size(x, 1), size_x+size_prepend+size_append))
@@ -107,7 +109,8 @@ contains
                 work(:, 1:size(work,2)-i) = work(:, 2:size(work,2)-i+1) - work(:, 1:size(work, 2)-i)
             end do
 
-            y = work(:, 1:size(work,2)-n_)
+            call move_alloc(work, y)
+            y = y(:, 1:size(y,2)-n_)
 
         end if